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Expert: - 12/22/2007


Question
please tell me sir, what is 63, 53, 33 grade cements?why is indicated?

Answer
Hi Mani,

This is related to the compressive strength at 28 days age, in Mpa, and is a function of how finely the cement is ground. Here is an extract from one of the cement manufacturers:

Ordinary Portland cement

OPC is manufactured in two grades — grade 43 and grade 53 — the numbers indicating the compressive strength obtained after 28 days, when tested according to the stipulated procedure.

In comparison, grade 53 and grade 43 types of cement have nearly identical chemical compositions, and the main distinction is in the degree of fineness. The grade 53 cement is ground to a greater degree of fineness compared to grade 43 cement. Grade 53 cement has a fineness index of 329 compared to 293 for grade 43 cement. The finer grade 53 cement has a faster setting time of 120 minutes compared to 155 minutes for the coarser grade 43.  

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Arshad Khan

Expertise

I can answer any questions to do with civil and structural engineering consultancy and construction industry in East Africa and the Middle East, and specifically with the analysis and design of reinforced concrete structures. My particular expertise is in the aseismic design and optimisation of tall buildings.

Experience

Employment history: 36 years in Construction and consultancy in the UK, Kenya, Tanzania, Uganda, Ethiopia, Eritrea, South Africa, Somalia, Zambia, Austria, Bahrain, Kuwait, Doha and the U.A.E.

Organizations
.Fellow of Institution of Structural Engineers (UK) .Fellow of Institution of Civil Engineers(UK) .Member of the Institution of Engineers, Kenya .Registered Engineer, ERB, Kenya .Member of the Architectural Association of Kenya (Engineers Chapter) .Chartered Engineer (UK)

Publications
•1984: International Conference on the Art and Practice of Structural Design, London •1994: 3rd Int. Kerensky Conference in Structural Engineering, Singapore •2008: International Conference on High-Rise Towers, Abu Dhabi

Education/Credentials
BSc, 1st Class Hons, in Building Engineering, University of Bath, UK MSc in Concrete Structures and Technology, University of London. Diploma of Imperial College, UK.

Awards and Honors
•Science Congress Special Award (for 2-seater Hovercraft - 1968) •Institution of Civil Engineers Award for outstanding performance at Bath University (1975) •Concrete Society Postgraduate study Bursary Award (1976) •Consular Representative for British High Commission, Nairobi. (1995 to 1998) •Examiner for Institution of Civil Engineers Professional Interviews, Nairobi. (1997 to 1998) •Branch Representative in Vienna for PI assessment for Inst. of Struct. Engrs. (1999 to date)

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